Glycosaminoglycans (GAG) are polysaccharides abundant in extracellular matrix and on cell surfaces. No precise biological role has been assigned to these substances, but they are thought to be involved in the maintenance of the integrity of the connective tissue. We have recently found that a subfraction of heparin and heparan sulfate enhance the binding of fibronectin to collagen by becoming associated with the fibronectin-collagen complex. This suggests that the presence of all three main components of extracellular matrix, collagen, fibronectin and GAG, may be necessary for the formation of the matrix. The disturbed deposition of extracellular matrix is often seen in transformed cells could be due to disturbances in the subfraction of GAG that enhance the association between fibronectin and collagen. We propose to isolate by affinity chromatography on fibronectin-collagen complexes the fractions of heparin and heparan sulfate with this activity and study their effect on the formation of extracellular matrix by normal and transformed cells. We will also determine whether cultured fibroblasts produce GAGs (or proteoglycans) which bind to fibronectin-collagen complexes and isolate them. Preliminary results suggest that such substances are found in spent culture media. We will study their effects on the growth characteristics of cells and determine whether differences in their expression or characteristics show variations that correlate with cellular parameters such as growth, transformation and malignancy. These studies may contribute to the understanding of the role GAGs play in the organization of extracellular matrix, the attachment of cells to this matrix, and how these functions are disturbed in malignant cells.